This works great if you’re installing on a clean, empty server, but if you’re upgrading a server that had an older version of Django on it (1.6.4 in my case) Ansible will act as if it’s installing 1.6.5, but when it’s done I still had version 1.6.4.

Note the line “Requested django==1.6.5, but installing version 1.6.4”. Thanks PIP!

It turned out to be a bug in PIP versions earlier than PIP 1.4, not Ansible. A little Googling turned up a page on Stackoverflow that pointed the finger at an old cached copy of 1.6.4 in the build directory, which I found in /tmp/pip-build-root.

I updated my Ansible YAML file to get rid of the temporary directory and now it works fine: